Pulverizer grate structure, including a curved-side filler piece



March 1, 1949.

G. O. VERCH PULVERIZER GRATE STRUCTURE, INCLUDING A CURVED-SIDE FILLER PIECE Filed Dec 4, 1943 @QMW Patented Mar. 1, 1949 UNITED STATES PATENT OFFICE PULVERIZEE GRATE STRUCTURE, INCLUD- ING A CURVED-SIDE FILLER PIECE George Watch; West Allis, Wis, assignor to Allis-Chalmers Manufacturing Company, Milwaukee, Wis., a, corporation of Delaware Application December 4, 1943, Serial No. 512,815-

8 Claims; 1

This invention pertains to rotary impact pulverizers and particularly to grate structure for such pulverizers.

It is already known in the art to assemble a grate in an arcuate guide frame by inserting a seriesoi grate bars and pairs of filler pieces locating and spacing the bars of the grating.

However, it has previously beenv necessary to use a different set of filler pieces for every thickness of bar which might be used in making up the grate and for every different curvature of grate whichmight be desired.

An object of the present invention is to create a, grate structure in which a single set of filler pieces will accommodate barsof any thickness while maintaining proper regularity of bar arrangement and substantially predetermined spacing between the bars.

More particularly it is an object to provide a form of grate spacer piece which canbe used to space bars of any'thickness and give firm spacing action in an arcuate grate by fuli planar engagement on one bar and engagement in a limited, central portion only on another adjacent bar.

The above and further objects may be best carried into effect in the manner fully described below withreference to the. accompanying drawing in. which Fig. I is a. cross-sectionalview of a pulverizer taken on-line I-I. of Fig. 2;

Fig. 2 is a vertical sectional view taken on line 11-11? of Fig. 1;

Fig; 3 isa. fragmentary sectional view of grate bar and. filler piece assembly using. light grate bars Fig; 4. is a fragmentary sectional view similar to' Fig. 3. using same: spacersv and: heavier grate bars;

Fig; 5 isa top detail: elevation of a. filler piece;

Fig. Sisadetailfiront elevation of a filler piece; and

Fig. 7 a fragmentary top elevation of a grate bar and filler piece assembly.

Like reference characters refer: to similar elements throughout the severalfignres of. the drawing.

A pulverizer l. of the rotary impact. type is provided with parallel. side walls 2 having. arcuate guide flanges 3 forming a grating, frame or seat. A movable frame member 4 is provided, capable of being moved endwise of flanges 3 by a clamping screw 5'- for a purpose which will appear hereinafter. A stoppiece or surface 5 is formed at one end of flanges 3. A grating through which pulverized material may pass is formed by in,-

serting into. the frame a. seriesv of pairs. of. filler pieces. '1. roughly T-shaped in cross. section. The legs Bf of the filler pieces. form bar spacing projections-between the adjacent ends. of successive bars 5, 9', which rest with one. edge on flanges 3'. The head, or web of the. filler piece 1 abuts adj'acentv bar ends forming coplanar shoulders to locate the bars end'wise between side walls. 2..

If it. were desirable to design a filler. piece which would be usable only with one radius of grate curvature and one. thickness. of'bar, a filler piece of the kind shown in U'.. S. Patent 1,625,554 to W. K; Liggett coul'dbe employed. However, in order to accommodate a thicker grate bar in the Liggett grate a different set of filler pieces would have. to be provided, having a different angle between. the sides of the leg or spacer portion be cause different thicknesses of rectangular grate bars placed on. an arcuate guide flange will have their sides at different angles to the radius of the radially inner corner of the grate bar. If the same set of fillers were used there would be spacing contact only at the inner edges of the bars and a series of such thicker bars could not be firmly clamped in place and held in true radially edgewise position.

The applicant provides a filler piece 1 shown in detail in Figs. 5 and 6 in which one face H of the leg or spacer projection 8 is cambered, that is, convexly curved, with respect to a mean plane inclined to the oppositely facingplanar face l2. That is, a high point of the face I I relative to its mean plane lies intermediate the edges of the planar side surface of an adjacent bar 9, 8", as clearly shown in Figs. 3 and 4. The leg or spacer projection 8 thus has a plane-convex form, the convex surface Hi being substantially cylindriform with its axis substantially parallel to the plane surface; The surface It could of course take substantially any known form of smooth convexly curved surface, so long as a high point relative toits mean plane lies intermediate the extremities of the piece radially, and surface I need not be a true right circuiar cylindrical surface. One end surface t3, the outer end radially of the piece, adapted to rest on. flange 3, is pref.- erably arcuate or convex in form with a curvature greater than that of any grate to which it might be applied within practical limits, so. as tomake a.

line contact. with said flange 3. in any normal position.

When the grate is assembled, the pieces I and grate bars 9 9, will takev positions as. shown most clearly in Figs. 3, 4. and '7. From Figs. 3 and. 4 it will be plainly evident that whether a thick bar 3 9' (Fig. 4) or a thin bar 9 (Fig. 3) is employed, the filler piece will assume a position with the face l2 firmly engaging a side face of an adjacent bar. The angle of the filler piece to a radius through it center will be different for different thicknesses of bars and the piece will therefore contact flange 3 at one line of surface i3 for one thickness of bar as shown in Fig. 3 and at another line of surface 13 for a thicker bar as shown in Fig. 4. The face I l of the filler piece I will contact the planar side surface of an adjacent grate bar 8 in a high point or line of tangency intermediate the extremities of said surface in a radial sense. Pressure exerted by bar 9 on the high point of surface M will cause the filler piece to be firmly and stably positioned relative to the succeeding bar for full facial contact therewith along planar surface [2.

It will be seen by Visualizing a displacement of one of the bars in Fig. 3 or Fig. 4 from a truly radial position, that the points of contact of the curved surfaces ll of the two spacers engaging such a displaced bar on opposite sides will be displaced radially of the grating so that a corrective couple is formed by the circumferential clamping forces acting laterally on the bars, which will tend to rectify the position of the displaced bar and spacer, resulting in a tendency for all bars to assume a radial arrangement relative to the grate curvature.

Now when a plurality of rectangular bars 9, or 9', or bars having substantially rectangular spaced portions, are inserted in the frame formed by side walls 2, flanges 3 and stop piece 5, with pairs of identical filler pieces 1 arranged to space and locate the adjacent ends of successive bars, the bars 9, or 9', regardless of thickness will take a radial edgewise position because the pieces will tend to form a corrective couple if the bars are displaced from true radial positions, as more fully explained hereinabove. The bars thus will be firmly and stably clamped into a regular arcuate grating by compression between stop surface 5 and movable frame member 4 by the action of clamping screws 5 acting on member 5 which is arranged to contact the end pieces of the series of bars 9, or 9', and move them endwise relative to flanges 3. The spacing between the radially inner corners of the bars will be substantially the same whether thin or thick bars 9, or 9', are used, and a different curvature of the grate frame will not affect the stability or true radial arrangement of the assembled grate, for filler pieces according to this invention are self-positioning regardless of the radius of curvature of the grate or the thickness of the bars, within practical limits.

The rectangular bars 9 or 9' are reversible end for end and edge for edge, thus forming a grate of maximum usable life. The upper ends of filler pieces 1 may be protected by side wall liner pieces l4 forming opposed arcuate channels with flanges 3 and side walls 2.

It should be noted that using identical filler pieces 1 the planar faces l2 of the pair of spacer portions 8 between a given pair of grate bars 9, or 9', will face in opposite directions as shown in Fig. 7. While this is a part of the invention and is highly desirable for economy in manufacture and ease of assembly and conducive to firmness due to the fact that each grate bar will bear on a flat spacer surface on each side, it will be understood that the invention is not limited to such identity and that paired orv right and left hand spacers may be used.

While a particular form of the invention has been specifically described and illustrated, it will be understood that such equivalents and modifications as may readily occur to persons skilled in the art are included within the invention which is limited only by the scope of the appended claims. 7

It is claimed and desired to secure by Letters Patent:

1. A pulverizer grating comprising a frame having opposed arcuate seats, a series of bars having spaced substantially rectangular portions engaging said seats, and a plurality of spacing elements positioned in said seats between adjacent said spaced portions of successive bars, said spacing elements each having a lateral surface engaging a lateral surface of one of said spaced portions and an oppositely facing convex surface having the form of a cylindrical segment engaging a lateral surface of the adjacent spaced portion of the succeeding bar substantially on a line of tangency parallel to and intermediate the edges of said lateral surface and intermediate the chordal extremities of said convex surface.

2. A pulverizer grating. comprising a frame having opposed arcuate seats, a series of bars having spaced substantially rectangular portions engaging said seats, and a plurality of spacing elements positioned in and engaging said seats between adjacent said spaced portions of successive bars, said spacing elements each having a lateral surface engaging a lateral surface of one of said spaced portions and an oppositely facing convex surface having the form of a cylindrical segment engaging a lateral surface of the adjacent spaced portion of the succeeding bar substantially on a line of tangency parallel to and intermediate the edges of said lateral surface and intermediate the extremities of said convex surface, at least one end surface of each said spacing element being convexly curved to a substantially greater degree of curvature than said arcuate seats and engaging one of said seats in internally tangent relation.

3. In an arcuate grating, a series of grate bars having spaced end portions with substantially parallel side surfaces, a filler piece comprising coplanar bar positioning shoulders engaging adjacent said spaced end portions of a pair of successive bars of said series and a bar spacing projection extending between said spaced end portions of said pair of successive bars, said bar spacing projection having a lateral surface perpendicular to said shoulders engaging a side surface of one of said spaced end portions and an oppositely facing convex lateral surface havingthe form of a cylindrical segment perpendicular to said shoulders engaging a side surface end of the adjacent spaced portion of the succeedingbar substantially in a line perpendicular to said shoulders intermediate the chordal extremities of said convex surface.

4. A pulverizer grating comprising a frame with spaced parallel plates having opposed arcu-' ate channels, a series of bars having substantially flat sided end portions, opposed pairs of filler pieces in said channels, each said filler piece having a pair of coplanar shoulders engaging adjacent ends of successive bars and locating said bars endwise between said plate and a spacing projection between adjacent end portions of sue-- cessive bars, each said spacing projection having a lateral surface perpendicular to said shoulders engaging a fiat side surface of one of s'aid'end portions and an oppositely facing convex lateral surface substantially perpendicular to said shoulders adapted to engage a flat side surface of the adjacent end portion of the succeeding bar only in a line intermediate the edges of said side surface and intermediate the extremities of said convex surface, and movable clamping means on said frame for circumferentially clamping said series of bars and filler pieces in said channels to form a firm uniformly spaced grating with said bars regularly arranged, substantially irrespective of the radius of curvature of the arcuate channels or the thickness of bars used with a given set of filler pieces.

5. A pulverizer grating comprising spaced parallel plates having opposed arcuate channels, a series of bars having substantially fiat side end portions, and opposed pairs of filler pieces in said channels, each said filler piece having a pair of coplanar shoulders engaging adjacent ends of successive bars and locating said bars endwise between said plates and a spacing projection between said bars, each said spacing projection having a plane lateral surface perpendicular to said shoulders engaging a flat side surface of one of said end portions, and an oppositely facing convex lateral surface substantially perpendicular to said shoulders adapted to engage a fiat side surface of the adjacent end portion of the succeeding bar substantially in a line intermediate the edges of said side surface and intermediate the extremities of said convex surface, said filler pieces of each said pair being identical and being rotated 180 relative to each other about an axis radial to said arcuate channels in assembly.

6. As an article of manufacture, a spacing element substantially T-shaped in cross section, comprising a head plate and a spacing projection, said spacing projection having a first side surface perpendicular to said head plate and a second oppositely facing convex side surface having the form of a cylindrical segment substantially perpendicular to said head plate.

7. As an article of manufacture, a spacing element for an arcuate grating composed of spaced bars, comprising a head plate and a spacing projection integral with said head plate, said spacing projection having a first side surface perpendicular to said head plate and a second oppositely facing convex side surface substantially perpendicular to said head plate, at least one end of said element being formed with an arcuate end surface perpendicular to said head plate and having a curvature in the plane of said head plate substantially greater than that of said grating.

8. As an article of manufacture, a universal spacing and positioning element for arcuate grates composed of bars having substantially flat parallel sided end portions, said element being substantially T-shaped in cross section and comprising a head plate portion and a spacing leg, said spacing leg having a first bar engaging side surface perpendicular to said head plate and a second oppositely facing bar engaging surface perpendicular to said head plate and convexly curved to the form of a cylindrical segment having a curvature sufiicient to prevent engagement of the extremities of said convexly curved second surface with the side surface of the engaged end portion of a grate bar, within practical limits as to bar thickness and radius of grate curvature.

GEORGE O. VERCH.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 53,860 Palmer Apr. 10, 1866 1,309,805 Lincoln July 15, 1919 1,624,886 Borton Apr. 12, 1927 1,625,554 Liggett Apr. 19, 1927 1,691,951 Alfred Nov. 20, 1928 2,049,083 Schaefer July 28, 1936 Certificate of Correction Patent N 0. 2,463,223. March 1, 1949.

GEORGE O. VEROH It is hereby certified that errors appear in the printed specification of the above numbered patent requiring correction as follows:

Column 4, line 39, claim 2, for the words the extremities read the ckordal emtremities; line 58, claim 3, after surface strike out end and insert the same in line 59, after spaced; column 5, line 17, claim 5, for side read sided;

and that said Letters Patent should be read with these corrections therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 5th day of July, A. D. 1949.

THOMAS F. MURPHY,

Assistant COmmz'ssz'oner of Patents. 

